A pesticide is a substance used for killing pets, which is often applied to agriculture, medicine, industry and home environment. In general, pesticides can be systemic or contact. The systemic pesticide is in corporation with plants. When pests eat plants, they also absorb pesticides. The contact pesticide is absorbed directly when pests are in contact with plants.
As to the hazards of pests to the growth and storage of crops, the crop yield may decrease greatly. As a result, the cost is increased to consumers. In order to achieve a high efficiency of crop productions, it is quite important for a pest control. Most pesticides are made of chemical materials. When the pesticide is applied to plants, it will permeate into the soil and into the plants from the roots to kill pests through the neurotoxin of the pesticide. However, most pests may be resistance to pesticides after a period of time. Thus, it is necessary to increase the dosage of the pesticide for plants. This not only causes soil acidification but also make the plants remain chemicals to influence the human health.